Act on churn

[benjaminbollen]

[maidsafe-highfive]

r? @inetic

(maidsafe_highfive has picked a reviewer for you, use r? to override)

[benjaminbollen]

running local network tests

[benjaminbollen]

also addresses #427

[benjaminbollen]

r? @dirvine

works really well; stopping work because I started to pile up several clean up issues in one commit;

the clean up work was provoked by the need for efficient traffic if we activate churn; the network should be much more lean with these cleanups already

[dirvine]

Reviewed 1 of 3 files at r1, 1 of 3 files at r2.
Review status: 2 of 4 files reviewed at latest revision, 1 unresolved discussion, all commit checks successful.

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^{src/routing_membrane.rs, line 624 [r2] (raw file):}
Should we should use lru cache for this rather than arbitrary timer

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Comments from the review on Reviewable.io

[dirvine]

Reviewed 2 of 3 files at r2.
Review status: all files reviewed at latest revision, 1 unresolved discussion, all commit checks successful.

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Comments from the review on Reviewable.io